1. Field of the Invention
The present invention relates to an attachment structure for a display unit, and makes it possible to fix a display unit to an instrument panel while easily positioning the former with respect to the latter.
2. Description of Related Art
As shown in FIG. 6, a center display unit (hereafter abbreviated as xe2x80x9cCDUxe2x80x9d) 2 is provided as a module, in which manipulation devices, indicators, and the like of audio equipment, an air conditioner, or the like are provided. The CDU is housed in an instrument panel I of an automobile at a central portion that is located between the driver""s seat and the front passenger seat.
A method of attaching the CDU 2 to the automobile body is as follows. As shown in FIG. 7, a resin frame 4 of the instrument panel I is formed with recesses 4b on the right and left sides of an opening 4a of the resin frame 4, and end surfaces of the recesses 4b are formed with CDU fixing holes 4c. Fixing pieces 3 of the CDU 2 are fitted into the recesses 4b, fixing holes 3a of the fixing pieces 3 are brought into registration with the CDU fixing holes 4c, and the CDU 2 is fixed to the instrument panel I with screws N. In attaching the CDU 2, the surface of a decorative plate 8, which is the front surface of the CDU 2, is positioned with respect to the surfaces of decorative members 5 that cover the surface of the resin frame 4, e.g., so as to be coplanar with the decorative members 5.
Alternatively, as shown in FIG. 8, metal brackets 6 that are provided on the back of the resin frame 4 are formed with fixing holes 6a. The fixing pieces 3 of the CDU 2 are inserted through notches 4d of the resin frame 4, fixing holes 3a of the fixing pieces 3 of the CDU 2 are then brought into registration with the fixing holes 6a of the metal brackets 6, and the CDU 2 is fixed with screws N.
The CDU attachment structure of FIG. 7 has an advantage that the surface of the decorative plate 8 of the attached CDU 2 can easily be positioned with respect to the surface of the decorative members 5 on the resin frame 4 in an accurate manner and dimensional management can be performed easily, because the CDU 2 is directly fixed to the resin frame 4. However, this attachment structure is not very strong because the heavy CDU 2 is directly held by the resin frame 4.
On the other hand, the CDU attachment structure of FIG. 8 has an advantage that it provides sufficient strength to hold the heavy CDU 2 because the CDU 2 is fixed to the metal brackets 6. However, since the CDU 2 is not directly fixed to the resin frame 7, that is, the metal brackets 6 intervene between them, a positional deviation tends to occur between the surface of the decorative plate 8 of the CDU 2 and the decorative members 5 of the resin frame 7, which makes it necessary to increase the accuracy of parts dimensions. This results in a problem that the cost of adjustment of parts molding dies is high. Another problem is that the CDU attachment takes a long time.
The present invention has been made in view of the above-described problems, and an object of the invention is therefore to make it possible to use metal brackets that are strong enough to hold a heavy CDU, to easily perform positioning between the metal brackets, a resin frame, and a CDU, and to easily and reliably position decorative surfaces of the resin frame and the CDU with respect to each other.
To attain these objects, the invention provides an attachment structure for attaching a display unit (e.g., a center display unit (xe2x80x9cCDUxe2x80x9d)) to a frame (e.g., a resin frame) of an instrument panel of an automobile so that the CDU is inserted in an opening of the resin frame. The attachment structure has a frame that includes bosses provided at first and second sides (e.g., right and left sides) of the opening. The bosses include first bosses projecting from a back surface of the frame and second bosses projecting from a front surface of the frame. The first and second bosses may share the same axes, i.e., may be coaxial. First fastener holes are also provided in the frame. Metal brackets are provided on the back of the resin frame. The metal brackets include first boss holes and second fastener holes at positions corresponding to positions of the first bosses and the first fastener holes, respectively, and a display unit includes second boss holes at positions corresponding to positions of the second bosses, and third fastener holes at positions corresponding to the first and second fastener holes. The CDU is positioned with respect to the frame by the interaction of the bosses and boss holes. The back-side bosses of the resin frame are inserted into the boss holes of the metal brackets and the front-side bosses of the resin frame are inserted into the boss holes of the CDU. In this state, screws are inserted into the fastener holes of the CDU, the resin frame and the metal brackets and engaged with the metal brackets, whereby the CDU is fixed to and supported by the metal brackets.
The bosses that project from the front and back surfaces of the resin frame and the resin frame may be formed by integral molding.
With the above configuration, the surface (hereinafter referred to as xe2x80x9cdecorative surfacexe2x80x9d) of a decorative plate of the CDU and the surfaces (hereinafter referred to as xe2x80x9cdecorative surfacesxe2x80x9d) of decorative members of the resin frame can easily be positioned with respect to each other in a state that the bosses sharing the same axes and respectively projecting from the front and back surfaces of the intermediate resin frame are fitted in the boss holes of the metal brackets and the CDU. In this positioned state, the CDU is fastened to the metal brackets with fasteners (e.g., screws), whereby the CDU can be attached to the instrument panel in such a manner that the decorative surfaces of the CDU and the resin frame do not become misaligned from each other.
The screws for fastening the CDU to the metal brackets are inserted into the fastener holes (e.g., screw holes) of the CDU and the resin frame and are engaged with the screw holes of the metal brackets, or nuts that are provided on the back of the metal brackets. Since the CDU is fastened to the metal brackets with the screws in this manner, the metal brackets can support the load of the CDU. Therefore, even if the CDU is heavy, there is sufficient support for the CDU and the resin frame need not be made strong enough to support the CDU.
Further, the above-described attachment structure enables positional adjustment between the CDU and the resin frame when the CDU is attached, which makes it unnecessary to set the dimensional accuracy of the CDU and the resin frame very high. This reduces the die adjustment cost and the work time for production of the CDU and the resin frame.
The bosses may have cylindrical shapes. One of the boss holes of the metal brackets may be a circular hole to be fitted with the boss on the same side and serves for the positioning boss, and the other boss hole may be an elongated hole having a minor-axis length that is substantially the same as a diameter of the associated boss. This arrangement enables easy position adjustment and prevents skewing.
With the above-described configuration, when the resin frame is attached to the metal brackets, one of the back-side, right and left cylindrical bosses is inserted into the circular hole that is one of the right and left boss holes of the metal brackets to attain positioning. On the other hand, when the other cylindrical boss is inserted into the elongated boss hole of the metal bracket, the elongated boss hole absorbs a dimensional error between the two cylindrical bosses and allows easy insertion of the cylindrical boss because the major axis of the elongated boss hole is larger than the outer diameter of the cylindrical boss.
Therefore, after inserting one boss into a corresponding boss hole, the other boss can still be inserted into its corresponding boss hole even if the distance between centers of the bosses is slightly different from the distance between centers of the boss holes.
In this manner, even if there are deviations between the interval between the right and left bosses of the resin frame, the interval between the right and left boss holes of the metal brackets, and/or the interval between the right and left boss holes of the CDU, since one of the boss holes of the metal brackets is an elongated hole which enables adjustment, the deviations between the intervals can be corrected for and the decorative surfaces of the CDU and the resin frame can easily be positioned with respect to each other.
During the above-described position adjustment, since the minor-axis length of the elongated boss hole is approximately equal to the outer diameter of the cylindrical boss, the circular boss hole of the metal bracket serves to position the metal frame and the elongated boss hole serves to prevent skewing while enabling position adjustment in the right-left direction.
The boss hole of the CDU corresponding to the elongated boss hole of the metal bracket may also be an elongated hole. As a further alternative, the screw holes of the CDU may have larger diameters than screws to be inserted therein in order to absorb dimensional errors.
A decorative surface may be formed by applying a resin cover to hide the screws (or bolts) and the bosses that are exposed by attaching the CDU to the resin frame. The resin cover may be provided with clip portions and the resin frame may have clip holes provided therein. The resin cover may be fixed to the resin frame by inserting the clip portions into the clip holes and engaging the clip portions with the clip holes.